A standoff between Pakistani government troops and a defiant Islamic cleric at a besieged Islamabad mosque has continued for a sixth day, with new reports of gunfire and explosions.

Abdul Rashid Ghazi, the top cleric at the Red Mosque, Lal Masjid, is still refusing government demands for the unconditional surrender vowing that he and his followers would rather die as martyrs.

Officials say around 60 militants and hundreds of radical students are inside the mosque.

Those inside the compound advocate the imposition of strict, Taleban-style Islamic law in Islamabad.

Ghazi said Saturday that government troops have killed about 70 students at a school in the compound. The government disputes that number, saying the death toll is closer to 19.

In other developments, security officials are investigating suspected links between an Friday's attempt to shoot down an airplane carrying President Pervez Musharraf and the siege on the Red Mosque. Shots were fired at the plane as it left a from a military base near Islamabad. The plane was not hit, and General Musharraf arrived safely at his destination.

Pakistani officials expressed concern over how details of the president's departure were leaked to the would-be assassins.